package network;

import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.SocketException;

public class UdpEchoServer {
    private DatagramSocket socket = null;

    public UdpEchoServer(int port) throws SocketException {
        socket = new DatagramSocket(port);
    }

    public void start() throws IOException {
        System.out.println("服务器启动!");
        while(true){
            DatagramPacket requestPacket = new DatagramPacket(new byte[4096],4096);
            socket.receive(requestPacket);
            String request = new String(requestPacket.getData(),0,requestPacket.getLength());
            String response = this.process(request);

            DatagramPacket responsePacket = new DatagramPacket(response.getBytes(),0,response.getBytes().length,
                    requestPacket.getSocketAddress());
            socket.send(responsePacket);
            System.out.printf("[%s:%d] req=%s,resp=%s\n", requestPacket.getAddress(),requestPacket.getPort(),
                    request,response);
        }
    }
        public String process(String request) {
            return request;
        }
        public static void main(String[] args) throws IOException {
        UdpEchoServer server = new UdpEchoServer(9090);
        server.start();
        }
}
